Messages in this thread Patch in this message | | | From | Zong Li <> | Subject | [PATCH v3 9/9] riscv: patch code by fixmap mapping | Date | Tue, 10 Mar 2020 00:55:44 +0800 |
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On strict kernel memory permission, the ftrace have to change the permission of text for dynamic patching the intructions. Use riscv_patch_text_nosync() to patch code instead of probe_kernel_write.
Signed-off-by: Zong Li <zong.li@sifive.com> --- arch/riscv/kernel/ftrace.c | 13 ++++--------- 1 file changed, 4 insertions(+), 9 deletions(-)
diff --git a/arch/riscv/kernel/ftrace.c b/arch/riscv/kernel/ftrace.c index c40fdcdeb950..ce69b34ff55d 100644 --- a/arch/riscv/kernel/ftrace.c +++ b/arch/riscv/kernel/ftrace.c @@ -8,6 +8,7 @@ #include <linux/ftrace.h> #include <linux/uaccess.h> #include <asm/cacheflush.h> +#include <asm/patch.h> #ifdef CONFIG_DYNAMIC_FTRACE static int ftrace_check_current_call(unsigned long hook_pos, @@ -46,20 +47,14 @@ static int __ftrace_modify_call(unsigned long hook_pos, unsigned long target, { unsigned int call[2]; unsigned int nops[2] = {NOP4, NOP4}; - int ret = 0; make_call(hook_pos, target, call); - /* replace the auipc-jalr pair at once */ - ret = probe_kernel_write((void *)hook_pos, enable ? call : nops, - MCOUNT_INSN_SIZE); - /* return must be -EPERM on write error */ - if (ret) + /* Replace the auipc-jalr pair at once. Return -EPERM on write error. */ + if (riscv_patch_text_nosync + ((void *)hook_pos, enable ? call : nops, MCOUNT_INSN_SIZE)) return -EPERM; - smp_mb(); - flush_icache_range((void *)hook_pos, (void *)hook_pos + MCOUNT_INSN_SIZE); - return 0; } -- 2.25.1
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